The acute injection of MMT into rats causes pulmonary edema localized to the lung alveoli, which is thought to be produced by a toxic metabolite formed in the lungs, possibly by cytochrome P450 2B1. It is not known whether this bioactivation occurs in human lungs.

Compounds emitted from the vehicular combustion of MMT as a gasoline additive include manganese oxide, phosphate and sulfate. Studies in rats report that these compounds, upon inhalation, can be taken up by olfactory nerve endings in the nose and retrogradely transported back into the brain, causing endogenous manganese levels in some areas (e.g., globus pallidus, striatum) to be more than doubled.

It has been suggested that the convulsive effect of MMT in mice is due to an inhibitory effect at the GABA(A) receptor-linked chloride channel.